The present invention relates to a suppressor of such noise as causes a variety of negative effects on electronic equipment in a vehicle.
Electronic devices placed in an automobile such as an FM radio receiver, a radio communications facility, and an electrically controlled fuel injection device, have recently come to be operated on a signal in the high-frequency range. The said devices are effected by the high-frequency current generated by an ignition system, a voltage regulator, and/or various kinds of switches including a horn relay, until noise is generated. The device thus effected is caused to be put in improper operation, and it normal function is suspended, requiring some proper countermeasures to correct the problem. In the conventional practice, no special attention has been given to the high-frequency properties of noise. For example, a noise suppressor such as a capacitor was set in place across the source of generation of the high-frequency current. In case a high-frequency current was deemed to have been generated secondarily in a wire by induction, either the wire was separated in terms of distance, or a shielded cable was specifically employed therefor, thus making the electrostatic coupling looser. However, the said measures have still involved numerous difficulties so that no desirable effects have been achieved, cost was increased, and /or no sufficient space or clearance for making the coupling loose enough could be obtained in a desirable manner.